chore: update README

Author: PerfectPan

readme.md

@@ -6,7 +6,7 @@ This plugin is powered by [prettier](https://github.com/prettier/prettier).
 
 ## Supported language
 
-JavaScript, TypeScript, HTML, CSS, Less, SCSS
+JavaScript, TypeScript, HTML, CSS, Less, SCSS, Markdown, JSON
 
 ## Usage